Move the ELF linker to elf/

This makes room for the Mach-O linker from
https://github.com/rui314/mold-macho, which will be in macho/. The
root Cargo.toml now only defines the workspace. build.rs looks for .git
in the parent directory, as the crate is no longer at the root of the
source tree.

Cargo.toml

@@ -1,22 +1,10 @@
-[package]
-name = "libmold"
-version.workspace = true
-edition.workspace = true
-rust-version.workspace = true
-description = "The internal library of the mold linker, whose API is not stable"
-license.workspace = true
-repository.workspace = true
-# tests/lib.rs belongs to the mold-tests workspace crate.
-autotests = false
-include = ["/src", "/c", "/build.rs", "/LICENSE", "/README.md"]
-
-# The linker is generic over the target. Instantiating it for all twenty
-# targets in one crate keeps the compiler on a single core for minutes, so
-# each target is instantiated in a crate of its own under arch/, and the
-# executable in cli/ dispatches to them.
+# The ELF linker in elf/ is generic over the target. Instantiating it for
+# all twenty targets in one crate keeps the compiler on a single core for
+# minutes, so each target is instantiated in a crate of its own under
+# arch/, and the executable in cli/ dispatches to them.
 [workspace]
-members = ["cli", "arch/*", "tests"]
-default-members = [".", "cli", "arch/*", "tests"]
+resolver = "3"
+members = ["cli", "elf", "arch/*", "tests"]
 
 [workspace.package]
 version = "3.0.0"
@@ -30,7 +18,7 @@ repository = "https://github.com/rui314/mold"
 # these versions equal to the workspace version above.
 [workspace.dependencies]
 libc = "0.2"
-libmold = { path = ".", version = "=3.0.0" }
+libmold = { path = "elf", version = "=3.0.0" }
 mold-arch-x86_64 = { path = "arch/x86_64", version = "=3.0.0" }
 mold-arch-i386 = { path = "arch/i386", version = "=3.0.0" }
 mold-arch-arm32 = { path = "arch/arm32", version = "=3.0.0" }
@@ -52,30 +40,6 @@ mold-arch-sh4be = { path = "arch/sh4be", version = "=3.0.0" }
 mold-arch-loongarch64 = { path = "arch/loongarch64", version = "=3.0.0" }
 mold-arch-loongarch32 = { path = "arch/loongarch32", version = "=3.0.0" }
 
-[dependencies]
-blake3 = "1.8.7"
-bstr = "1"
-cpp_demangle = "0.5.1"
-crc32fast = "1"
-flate2 = { version = "1", default-features = false, features = ["zlib-rs"] }
-getrandom = "0.4.3"
-hashbrown = "0.17.1"
-libc.workspace = true
-libz-rs-sys = "0.6.8"
-memchr = "2.8.3"
-memmap2 = "0.9"
-# std has no 64-bit atomics on hosts such as 32-bit PowerPC.
-portable-atomic = "1"
-rayon = "1"
-rustc-demangle = "0.1"
-uuid = { version = "1.27", default-features = false, features = ["v4"] }
-xxhash-rust = { version = "0.8", features = ["xxh3"] }
-zlib-rs = { version = "0.6.8", default-features = false }
-zstd = "0.13"
-
-[build-dependencies]
-cc = "1"
-
 [profile.release]
 panic = "abort"
 # Copying generic and inline functions once per crate instead of once per

arch/README.md

@@ -5,7 +5,7 @@ one target architecture. Separate crates let Cargo compile the architectures
 in parallel. Instantiating all targets in one crate leaves a long serial
 compilation step.
 
-The shared linker implementation lives in [`src/`](../src/), with
-target-specific code in [`src/arch/`](../src/arch/). These crates provide
+The shared linker implementation lives in [`elf/`](../elf/), with
+target-specific code in [`elf/arch/`](../elf/arch/). These crates provide
 entry points that the [`cli/`](../cli/) executable selects for the input
 files' target.

elf/Cargo.toml

@@ -0,0 +1,35 @@
+[package]
+name = "libmold"
+version.workspace = true
+edition.workspace = true
+rust-version.workspace = true
+description = "The internal library of the mold linker, whose API is not stable"
+license.workspace = true
+repository.workspace = true
+
+[lib]
+path = "lib.rs"
+
+[dependencies]
+blake3 = "1.8.7"
+bstr = "1"
+cpp_demangle = "0.5.1"
+crc32fast = "1"
+flate2 = { version = "1", default-features = false, features = ["zlib-rs"] }
+getrandom = "0.4.3"
+hashbrown = "0.17.1"
+libc.workspace = true
+libz-rs-sys = "0.6.8"
+memchr = "2.8.3"
+memmap2 = "0.9"
+# std has no 64-bit atomics on hosts such as 32-bit PowerPC.
+portable-atomic = "1"
+rayon = "1"
+rustc-demangle = "0.1"
+uuid = { version = "1.27", default-features = false, features = ["v4"] }
+xxhash-rust = { version = "0.8", features = ["xxh3"] }
+zlib-rs = { version = "0.6.8", default-features = false }
+zstd = "0.13"
+
+[build-dependencies]
+cc = "1"

elf/build.rs

@@ -65,9 +65,11 @@ fn git_hash(source_dir: &Path) -> Option<String> {
 }
 
 fn main() {
-    let source_dir = PathBuf::from(std::env::var("CARGO_MANIFEST_DIR").unwrap());
+    // This crate is in elf/ of the source tree.
+    let manifest_dir = PathBuf::from(std::env::var("CARGO_MANIFEST_DIR").unwrap());
+    let source_dir = manifest_dir.parent().unwrap();
     let version = std::env::var("CARGO_PKG_VERSION").unwrap();
-    let version = match git_hash(&source_dir) {
+    let version = match git_hash(source_dir) {
         Some(hash) => format!("mold {version} ({hash}; compatible with GNU ld)"),
         None => format!("mold {version} (compatible with GNU ld)"),
     };